/Engine/Source/Editor/UnrealEd/Public/Bookmarks/IBookmarkTypeTools.h
Compacts the available bookmarks into mapped spaces. Does nothing if all mapped spaces are already filled, or if no bookmarks exist that are not mapped.
void CompactBookmarks ( class [FEditorViewportClient](API\Editor\UnrealEd\FEditorViewportClient) * InViewportClient ) const